The present invention relates to electronic apparatuses of the xe2x80x9cion generatorxe2x80x9d type. Such apparatuses enable a certain density of ions (e.g. of negative oxygen ions in air) to be maintained within an enclosure or in premises in order to make the place where ions are being diffused more healthy.
An application of the invention relates to maintaining a certain density of ions, e.g. negative oxygen ions in air, inside any closed or semi-open enclosure or premises having a ventilation system in order to restore health to the place where controlled ion diffusion is being applied.
Such an ion generator apparatus is known from document WO 96/02966.
The structure of that known apparatus essentially comprises:
a first subassembly constituted by an electron optics system; and
a second subassembly constituted by a power supply unit delivering a high voltage of the order of 4 kV to 5 kV between an output S and a common ground M, and at an impedance of about 100 Megohms; said second subassembly supplying said electron optics with the high voltage required for producing ions.
In more detail, the electron optics structure comprises the following elements which are shown diagrammatically in FIG. 1.
A first plate 2 of insulating material prevents any emission of electrons (corona effect) from around the rear of the apparatus.
A conductive second plate 4 carries on its rear face emissive xe2x80x9cpointsxe2x80x9d such as the point 6. An insulating third plate 8 secured to the plate 4 is situated in front of it.
The xe2x80x9cpointsxe2x80x9d 6 are constituted by long thin needles of stainless metal (Ag), and each has an emissive free end with a radius of a few micrometers.
An electron emission matching structure is constituted by a dielectric xe2x80x9csheathxe2x80x9d 10 and a dual cone structure 12 secured to the sheath and made of the same insulating material. The matching structure also has an internal plane structure (plate 14) secured to the cone structure, extending therefrom and made of the same insulating material. It is fixed to the outside wall 22 of the housing containing the apparatus.
A system of composite plates 16, 18 has an insulating inside face 18 and a conductive top face 16 connected to ground. A hole 20 allows the sheath and the emitter needle to pass therethrough.
A final plate 22 constitutes a housing containing the apparatus. It is made of a material that is a very poor conductor, and it is connected to the conductive plate 16. A xe2x80x9cleakagexe2x80x9d resistor 24 represents the real resistance of the plate 16 for draining off the charge taken from the local space charge that results from the points emitting electrons.
In that apparatus, the plate 16 carried by the insulating plate 18 is connected to ground (zero potential), and the emitter needles are sheathed in dielectric.
The zero equipotential is determined by the field plate 16, its distribution depending on the positions and the length of the needles, and on the characteristics of the dielectric sheath and of its distal cone 26.
Because of the relatively high permittivity of the sheath and its distal cone, the zero equipotential xe2x80x9cdrops downxe2x80x9d practically onto the outside surface of said sheath.
In theory, this serves to ensure that an electric field of very high maximum value is present at the free end of the needle.
Such an apparatus operates at a voltage of less than 4.5 kV.
There also exist apparatuses that operate at voltages lying in the range 6 kV to 12 kV.
All those apparatuses present certain drawbacks.
Firstly, their performance is limited and incapable of ensuring long term and consistent production of ions. In particular they do not make it possible to cause a negative flux of ions to circulate constantly in the site or the enclosure to be treated.
Nor do they make it possible to provide and extend the flux of ions and the diffusion of ions throughout the entire enclosure or premises to be treated, and they are not very reliable concerning actual production of ions.
Known apparatuses also have rather low efficiency in producing ions after they have been in use for a while. In particular, after they have been used several times, they are found to be poor at producing oxygen ions effectively.
Those that operate at a voltage in excess of 6 kV are dangerous because of the aggressivity and the toxicity of the peroxiding substances they produce, such as ozone and nitrogen oxides. They also give rise to electrostatic fluxes. In addition, the use of voltages that are too high is very difficult to control or master, and is therefore very dangerous for an everyday application.
Apparatuses which operate at a voltage that is less than or equal to 4200 volts, and in particular those of the type described above with reference to FIG. 1, implement electrical power supply methods and manufacturing methods that tend to create a matching system for supplying power and creating an ion flux.
However, whatever the systems or protective methods in existence heretofore, they do not manage to avoid creating rubbing and air circulation and diffusion inside the housing, thereby building up static charge and/or favoring the formation of peroxide type compounds. Unfortunately, static charge reduces the yield of the mass of ions created.
Nor do such apparatuses ensure that the emitter needles are consistent and stable, nor do they ensure that the production from each needle is consistent, regular, and controllable in order to produce ion fluxes having a lifetime that is sufficient for enabling an intended or identified premises to be treated normally and durably.
The apparatus described in document WO 96/02966 also requires a conical opening 28 which makes it possible to touch the needles, which is dangerous in some applications, in particular in cars or in day nurseries.
Furthermore, the electrical connection between the plates 16 and 22 is provided by means of an electric wire, thus requiring additional connections and complicating the apparatus and manufacture thereof. These connections also create a deficiency in the high voltage power supply, and do not prevent losses or static charges. The apparatuses therefore cannot genuinely ensure high quality production of ions and dispersal of the ion flux into the atmosphere.
Corona effects also occur in those known apparatuses. These effects cause polluants to be deposited in the V-shaped zones 30 constituted by the distal cones 26 and the conical openings 28. These zones are in contact with the atmosphere and the flows of air circulating therein, thereby creating parasitic compounds of peroxide or other types. Corona effects prevent known apparatuses from operating effectively.
Finally, that type of apparatus does not provide an effective and long-lasting solution to treating the intended enclosure, and to restoring the place to health.
Such apparatus also fails to create genuine isolation and genuine sealing, because it needs external power supplies and resistances in order to operate.
Finally, the structure of the sheath 20 secured to the cone 12 itself secured to the plates 14, is complex to manufacture industrially.
In both cases, a zone of plasma extends very widely from the emitter points. That gives rise to various peroxides being formed which are dangerous for human and animal health, such as NOx, and which also serve to reduce the desired emission of ions by an attraction and screening process.
In addition, the magnitudes of the electric fields in both of the above-mentioned existing devices are highly random in the vicinity of the emitter points.
In order to favor diffusion, dispersal, and circulation of ions, some apparatuses include a driving fan. That gives rise to a system that is expensive, that consumes excessive energy, and that produces noise disturbance. Furthermore, such a system stirs up the air causing dust to collect on the blades of the fans or the propulsion system, thereby increasing air rubbing phenomena, thus making electrostatic disturbances more dense, and in turn reducing the ion flux emitted into the enclosure or volume to be treated.
In another aspect, known apparatuses are unsuitable for adapting to a variety of premises or environments.
If a given apparatus is installed in certain premises, there are no means enabling its production of ions to be modified as a function of how the premises are occupied, whether the xe2x80x9coccupationxe2x80x9d relates to humans or to the environment constituted by furnishings or coverings on the walls of the premises. Nor does any system enable the production of ions to be matched to the place where the premises is to be found. Unfortunately, requirements are not the same depending on where the premises is situated, for example in a city or in the country.
Finally, known apparatuses do not enable an apparatus to be made in which the number of emitter needles or points is more than just a few. At best, known apparatuses have fewer than a score of needles.
The invention firstly provides apparatus for generating ions in an atmospheric or gaseous medium, the apparatus comprising:
one or more needles, each presenting a shank and an emitter end;
a sheath of composite material which surrounds the shank of each needle; and
means for applying a voltage between two portions of the shank of each needle.
The composite material comprises an unsaturated polyester reinforced with glass fibers.
The use of such a composite material as the sheath material provides a considerable improvement concerning the emission of electrons and the production of ions that are actually obtained.
Such a material can have resistivity equal or substantially equal to 1012 xcexa9.m, whereas document WO 96/02966 recommends using a material of resistivity greater than or equal to 1015 xcexa9.m.
Selecting this material also avoids the need to make a distal conical structure in the vicinity of the end of each needle and secured to the sheath, and also avoids the need to make a proximal conical structure adjacent to the emitter end of each needle.
The apparatus for generating ions (positive ions or negative ions) is thus much easier to manufacture, and the zero potential lines drop down along the sheath without any need for conical structures.
The sheath made around the needle can be cylindrical in shape, without having a conical end portion.
The composite material can contain 50% to 90% by weight of glass relative to the total weight of the material. It can also include mica.
The needles can be made of a material selected from titanium, platinum, a compound of titanium and platinum, silver, stainless steel, brass, nickel, and an alloy of these materials.
The means for applying a voltage between two portions of the body of each needle comprise, for example, first and second plates situated at two different heights along each sheath, and means enabling a high voltage to be applied between the two plates.
An electrical power supply circuit can be incorporated on one of the plates. Thus, connections between the ionizer apparatus and the outside are reduced, thereby achieving a corresponding reduction in problems of micro-drafts or leaks from the outside towards the inside of the apparatus, and thus avoiding the problems mentioned above in the introduction.
In an embodiment, one of the plates includes an assembly constituted by the high voltage power supply and electronic means enabling said voltage to be applied along the body of each needle.
In another particular embodiment, for apparatus having a plurality of needles, each needle can be surrounded by a sheath, with the sheaths being interconnected in pairs.
This favors mechanical holding of the needles and also prevents instabilities in the production of ions, and prevents the production of interfering compounds.
The sheaths can thus be paired by means of a web of material that is identical to the material of the sheaths, with the two sheaths of each pair and the web being formed as a single block. A structure is then obtained that is highly advantageous from the industrial manufacturing point of view.
In another aspect, the invention also provides a circuit for regulating an ionizer apparatus, the circuit further including means for regulating the voltage applied between the two portions of the shank of each needle, e.g. from a transformer or a transmitter-regulator; the apparatus thus makes it possible to control ion diffusion.
The ionizer apparatus may advantageously be of the type described above in the context of the present invention.
In a particular embodiment, the voltage regulator means comprise means for measuring the quantity of ions produced by the apparatus, means for comparing said quantity of ions produced with an ideal quantity required, and means for varying the applied voltage as a result of the comparison between the quantity of ions produced and the quantity of ions required.
The ideal quantity of ions required can be determined on the basis of a corrected volume taking account of the real volume of the premises in which the ion generator apparatus is installed, and also the content of the premises and/or its environment.
Thus, a user can regulate the operation of ionizer apparatus as a function of its environment, e.g. of human occupation and/or of furnishings and/of wall coverings in the premises, or indeed as a function of the place where the premises is to be found.
Such regulation can also be performed automatically, on a single occasion or regularly over time.
The means for varying the applied voltage can be automatic means or manual means.
The invention also proposes an ion detector comprising:
means for sensing ions or a quantity of ions in an atmosphere;
indicator means for indicting the presence of ions; and
switch means for switching the indicator means as a function of the quantity of ions sensed by the ion sensor means.
By way of example, the switch means comprise a transistor biased by a voltage source when switching occurs.
The detector can be used with the above-described voltage regulator means.